TM 9-2320-364-102-224 2-26. PERSONNEL HEATER (CONT).c.Turn Windshield Defrost ON/OFF.(1)Pull the DEFROST control lever (2) to the left to add more air flow to thewindshield.(2)Set the FAN control switch (3) to LO, MEDIUM, or HI position.(3)Set the FAN control switch (3) to OFF.d.Turn Cab Ventilator ON/OFF.(1)Push the HEAT control lever (1) to OFF position.(2)Push the AIR control lever (4) to RECIRC position.(3)Push the DEFROST lever (2) to DEF position.(4)Pull the cab ventilator knob (5) out (approximately 1.5 in. [4 cm]).(5)Set the FAN control switch (3) to LO, MEDIUM, or HI position.(6)Rotate four blower vents (6) for desired air flow.(7)Set the FAN control switch (3) to OFF.